LOS ANGELES — Minutes before a gunman opened fire in a Los Angeles International Airport terminal last fall, killing a security screener and wounding three other people, the two armed officers assigned to the area left for breaks without informing a dispatcher as required.

The Los Angeles Airport Police Department officers were outside Terminal 3 when authorities say Paul Ciancia opened fire with an assault rifle, two law enforcement officials said. The officials requested anonymity, saying they were briefed on the shooting but were not authorized to speak publicly about the investigation.

As terrified travelers dived for cover, TSA officers — who are unarmed — fled the screening area without hitting a panic button or using a landline to call for help. It took a call from an airline contractor to a police dispatcher, who then alerted officers over the radio — a lag of nearly 90 seconds, the officials said.

Before officers could get to the scene, Ciancia fatally wounded TSA Officer Gerardo Hernandez and then headed to the screening area where he shot two more agents and a traveler, authorities said. Ciancia was subdued after being wounded by officers in the gate area of the terminal.

As part of a review prompted by the shooting, the TSA is considering allowing screeners to carry phones while working, according to an agency official close to the inquiry who requested anonymity.

Officials need to decide whether the ability for agents to call for help in an emergency trumps the potential distraction from the phones.

The new details about the whereabouts of the two officers and communication issues come as authorities review the overall response, including whether emergency medical personnel were forced to wait longer than necessary to remove Hernandez so he could be taken to a hospital.